Beverly K. Philip, M.D., Chair
Committee on Ambulatory Surgical Care

ropofol is a popular drug used for sedation among anesthesiologists. With propofol the patient reaches the desired state of sedation quickly, recovers quickly and has little nausea. Increasing numbers of diagnostic and therapeutic procedures, however, are being done outside of conventional operating rooms with sedation administered by the proceduralist supervising a registered nurse. This sedation has conventionally been done with an opioid and a benzodiazepine. These proceduralists have seen the potential advantages of sedation with propofol. The obvious good outcomes with propofol, however, mask the less obvious risks — a depth of sedation that changes rapidly and profoundly with abrupt onset of airway obstruction and apnea and the lack of a specific antidote. The use of propofol by physicians and nurses not trained in anesthesiology has grown steadily over the past several years and is now receiving much attention in the national media.

Other physician groups assess the risks and benefits of propofol sedation differently than anesthesiologists. Gastroenterologists have published reports and studies about their experiences with nurse-administered propofol sedation (NAPS) since 1998. In March 2004, three gastroenterologist organizations released a statement supporting NAPS; a review of the issues including a link to that statement can be found at <www.ASAhq.org/news/propofoluse.htm>. The published gastroenterology literature includes three large series totaling 13,726 generally healthy patients without major complications or resuscitation by an anesthesiologist. Each series, however, reports adverse events, including “prolonged apnea,” “hypoxemia,” desaturations < 90 percent and < 85 percent despite nasal oxygen, laryngospasm and conversion to general anesthesia due to restlessness as well as colonic perforations.^1,2,3 The reason given for avoiding the involvement of an anesthesia specialist was the probability of lower cost.¹

Other physicians who advocate propofol sedation include emergency medicine (EM) physicians. The EM literature on propofol sedation contains smaller series (20-54 adults), each of which report adverse outcomes, including apnea, respiratory depression (ETCO₂>50 mmHg, SpO₂< 90 percent, or absent CO₂ waveform) and need for assisted ventilation.⁴ In a 2003 editorial endorsing the use of propofol, Green and Krauss identified the risk of aspiration as the most serious sedation risk in EM, not respiratory depression.⁴ They recommended giving supplemental oxygen and to “avoid assisting ventilations” to minimize aspiration risk, preferring to “simply ‘wait out’ an occurrence of propofol-associated respiratory depression” in these nonfasted patients. They acknowledge that “some or most” patients cross the boundary between deep sedation and general anesthesia.

Office dentistry also is looking toward solo operator-administered propofol sedation, possibly with continuous infusion or patient-controlled sedation.⁵

The obvious question is, how do these safety data and outcomes compare to propofol sedation when administered by anesthesiologists? The answer is, we have no published comparative data. The absence of reports of severe morbidity or mortality by other physician groups, however, should be compared with anesthesia morbidity/mortality for healthy patients, which is generally believed to be 1 in 300,000.

Anesthesiology departments may be called on to help develop criteria for the administration of propofol sedation by nonanesthesia providers in their facility. To begin, ASA has provided us with definitions of the depths of sedation and anesthesia:

Moderate Sedation/Analgesia (Conscious Sedation) is a “drug-induced depression of consciousness during which patients respond purposefully to verbal commands, either alone or accompanied by light tactile stimulation. Reflex withdrawal from a painful stimulus is NOT considered a purposeful response.”⁶

Deep Sedation/Analgesia is a “drug-induced depression of consciousness during which patients cannot be easily aroused but respond purposefully following repeated or painful stimulation.”6 If the patient “loses consciousness and the ability to respond purposefully, the anesthesia care is a general anesthetic.”⁷

With these definitions, we need to consider the concept of rescue. ASA guidelines state that “even if moderate sedation is intended, patients receiving propofol … should receive care consistent with that required for deep sedation. Accordingly practitioners administering these drugs should be qualified to rescue patients from any level of sedation, including general anesthesia.”⁸

In 2004, the ASA House of Delegates approved a definition of rescue: “Rescue of a patient from a deeper level of sedation than intended is an intervention by a practitioner proficient in airway management and advanced life support. The qualified practitioner corrects adverse physiologic consequences of the deeper-than-intended level of sedation (such as hypoventilation, hypoxia and hypotension) and returns the patient to the originally intended level of sedation. It is not appropriate to continue the procedure at an unintended level of sedation.”⁹

When anesthesiology departments help to develop criteria for propofol sedation by nonanesthesia providers, there are legal issues to consider. As reviewed by Judith Jurin Semo, Esq., Squire, Sanders & Dempsey, this assessment begins with the manufacturer’s Food and Drug Administration-approved package insert. The “Warnings” section states that propofol used for monitored anesthesia sedation or anesthesia “should be administered only by persons trained in the administration of general anesthesia and not involved in the conduct of the surgical/diagnostic procedure.”

A second issue relates to nurses participating in the administration of propofol. State regulations vary, and it is important to confirm that all individuals are acting within the scope of authority of their license. The facility’s accrediting organization also may have relevant standards. The Joint Commission on Accreditation of Healthcare Organizations and the Accreditation Association for Ambulatory Health Care require that individuals who administer sedation must be competent to rescue, while the Ambulatory Association for Accreditation of Ambulatory Surgical Facilities requires that propofol be administered only by an anesthesiologist or a nurse anesthetist.

A fourth issue relates to informed consent. Has the patient been given adequate information on the risks of propofol sedation/anesthesia and the qualifications of the individual administering and monitoring the sedation? Furthermore, anesthesiology departments should be aware whether they are obligated to supervise all anesthesia or sedation administered in the institution and therefore would be responsible.

In response to requests from its members, ASA developed the “Statement on Safe Use of Propofol,” approved in October 2004, which in addition to the definition of rescue provides criteria for safe administration of the drug.9 The statement addresses the education and training needed for the physician responsible for the use of sedation/anesthesia and the need for immediate availability of the physician after sedation until the patient is medically discharged. It also addresses the education and training of the practitioner monitoring the patient, who should be completely dedicated to that task. Personnel should be qualified to rescue patients from general anesthesia. The statement addresses appropriate physiologic monitoring during propofol administration as well as equipment needed.

Propofol is an anesthetic drug, and ASA believes that the involvement of an anesthesiologist in the care of every patient undergoing anesthesia is optimal.⁹ Other providers, however, do administer this drug, and we need to have the information to help set up policies and care processes so that all patients will receive safe care.

References:
1. Rex DK, Overley C, Kinser K, et al. Safety of propofol administered by registered nurses with gastroenterologist supervision in 2000 endoscopic cases. Am J Gastroenterol. 2002; 97:1159-1163.

2. Walker JA, McIntyre RD, Schleinitz PF, et al. Nurse-administered propofol sedation without anesthesia specialists in 9152 endoscopic cases in an ambulatory surgery center. Am J Gastroenterol. 2003; 98:1744-1750.

3. Heuss LT, Schnieper P, Drewe J, et al. Risk stratification and safe administration of propofol by registered nurses supervised by the gastroenterologist: A prospective observational study of more than 2000 cases. Gastrointest Endosc. 2003; 57:664-671.

4. Green SM, Krauss B. Propofol in emergency medicine: Pushing the sedation frontier.  Ann Emerg Med. 2003; 42:792-797.

5. Yagiela JA. Making patients safe and comfortable for a lifetime of dentistry: Frontiers in office-based sedation.  J Dent Educ. 2001; 65: 1348-1356.

6. ASA Continuum of Depth of Sedation: Definition of General Anesthesia and Levels of Sedation/Analgesia. Approved 1999; last amended 2004. <www.ASAhq.org/publicationsAndServices/standards/20.pdf>.

7. ASA Position on Monitored Anesthesia Care. Approved 1986; last amended 2003. <www.ASAhq.org/publicationsAndServices/standards/23.pdf>.

8. ASA Practice Guidelines for Sedation and Analgesia by Nonanesthesiologists. Approved 2001. <www.ASAhq.org/publicationsAndServices/sedation1017.pdf>.

9. ASA Statement on Safe Use of Propofol. Approved 2004. <www.ASAhq.org/publicationsAndServices/standards/37.pdf>.

Beverly K. Philip, M.D., is Professor of Anesthesia, Harvard Medical School and Director, Day Surgery Unit, Brigham and Women’s Hospital, Boston, Massachusetts.